[en] All living organisms exist and evolve under the permanent impact of the ionizing radiation of the natural background. Scientific data show presence effects of adapting and simulation at low doses exposure in the range of natural background radiation. This beneficial effects, known as hormetic, are proved on molecular, cellular or organism level as well as population. The article presented reviews the phenomenon of radiation hormesis and the epidemiological evidences that confirm its existing. The disputed topics of the epidemiological investigations are discussed